How do you get a CI up and running fast from scratch? How do you automate versioning?

So, I've got my own little personal projects with which I'd like to do this. I'm not really sure how to do it though.

I use CircleCI for instance but I haven't figured out how to get it to make deployments. I am also not quite sure how you go about automating versioning. It seems dumb to be changing version numbers manually.

I don't suppose someone could help me with that.